DOCSLIB.ORG

The Physical Aspects of Fish Locomotion

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Physical Aspects of Fish Locomotion THE PHYSICAL ASPECTS OF FISH LOCOMOTION BY E. G. RICHARDSON, B.A., PH.D., D.SC. (Armstrong College, Newcastle on Tyne.) (Received January i, 1935.) (With Eight Text-figures.) I. INTRODUCTION. THE mechanism by which a fish is able to dart through a heavy medium like water with little apparent effort has long been a matter of interest to zoologists. Before the arrival of the cinematograph in its modern form, Marey (1884) obtained a series of " chronophotographic" records of fishes in movement to demonstrate the sinusoidal motion, while more recently Magnan (1930) and Gray (1933) have taken cinematograph pictures at the rate of 10-20 per sec, in which the fish is seen swim- ming behind a reticule, thus making detailed study of the mode and rate of pro- gression possible. Houssay (1912) and Breder (1926) have also made contributions to this problem. Their work will be noted later. With the general adoption of streamlined form for all bodies which have to move rapidly through air or water, the attention of workers in hydrodynamics has been focused on the same problem. Indeed, the extensive researches of Magnan were subventioned by the French Air Ministry. It is from this aspect that the author is interested in the subject. There appear to be two possible explanations to account for the rapidity of movement of a fish through the water, viz. (1) that in virtue of the mucus on its surface it may possess a resistance lower than that of the same shape when unlubricated, (2) that in virtue of its flexibility it cleaves the water with less re- sistance than if rigid. If either of these facts can be substantiated it is obviously of great importance to aircraft and ship design. II. RESISTANCE MEASUREMENTS. Although Houssay made measurements of the resistance of wooden models of fish towed through the lake of the ficole Militaire at Paris, the only measurements on fishes were those of Magnan deduced from cinema photographs of the weighted bodies of fish freely falling in a water tank. The photographs are scarcely clear enough for the exact deduction of the rate of fall. Indeed Magnan decides that the space : time curves are exact parabolas, which as he rightly deduces, implies that the resistance is independent of the velocity. He does not, however, complete the argument which is that if the parabolic law is followed the velocity increases without limit, a condition only fulfilled on free fall in a vacuum. A body falling in a 64 E. G. RICHARDSON resisting medium must sooner or later reach a constant velocity, determined by the balance between gravity and resistance, which can then be determined as a function of the terminal velocity. The author decided to determine the rate of fall of fishes over various distances by a direct chronographic method. A tank 8 ft. high and 1 ft. 6 in. square was filled with water and equipped with starting and stopping devices for the object whose fall was to be investigated. The former device was arranged so that the fish could be started from a little below the surface, the latter was a tray which could be lowered by cords passing over pulleys to counterpoise weights. The fish was held in an electromagnetic grip by its tail. Breaking the electric circuit released the fish and simultaneously released the brake of a Wood's chronograph. When the nose of the fish hit the lower stage, which was a pivoted gauze network, it broke a contact, which stopped the chronograph again. As will be seen from the diagram of the apparatus (Fig. 1) this contact had to be arranged in a vessel above water, otherwise it did not break smartly, the water being a conductor of electricity. With this apparatus the time could be read to 0-002 sec, while the distances were measured by telescope to 1 mm. The freshly killed fish, deprived of all its fins except the caudal fin, was loaded by lead shot in the mouth. Trouble was experienced at distances of fall exceeding 2 ft. owing to the flexibility of the fish which often led it to describe a curved trajectory. Later a wire stiffener was pushed into the body to keep the fall vertical. At any given distance, times were repeated until a minimum had been established. After each fall the lower stage was raised to retrieve the fish. When a series of falls at various distances and weights had been made, the fish was carefully measured and a template made. Subsequently a wooden model was made to the template, loaded in the scooped-out interior by lead shot and provided with an aluminium tail. The time of fall of the model in the tank was then determined under three conditions of surface, i.e. (a) roughened, (b) smoothed and polished, (c) greased with oil. Writing the equation of motion of the falling body in the form , m dt=mg~R' where the first term represents the downward force on the body at the instant when its velocity is v, the second term is the weight of the body in the water, or buoyancy, and the third is the resistance. We will write the latter as a function of v in the form kvn, so that , m =m g + kvn. at n may have, in practice, values between o and 2; (a) if n = o, v = ( ) t, the \m ml acceleration is constant and we have the case postulated by Magnan; (b) if n = 1 (Stokes' law), fc the terminal velocity is m'glmk; (c) if n = 2 (Newton's law), v = c tanhgjc, where c is the terminal velocity =Vm'glmk. In case (c) the terminal velocity is of course less, The Physical Aspects of Fish Locomotion 65 ceteris paribus, and reached in a shorter time. On Fig. 2 are plotted the displace- ment : time curves for a mackerel and a herring loaded by different weights to show that a terminal velocity, indicated by the graph becoming a straight line, is in To starting switch of chronograph [*o stopping switch of chronograph Fig. 1. Tank for time of fall of fishes and models. practically every case attained within the depth of the tank. Probably Magnan's failure to detect a terminal velocity is due to his not having carried the distances far enough. (Although he had at his disposal a tank 3 metres deep, the displacement: time curves on which he bases his n = o deduction seem not to extend beyond half a metre.) Table I gives the resulting data in the form of weight in water (W) and corresponding terminal velocity (V). These are subsequently plotted in the form JEB-XIIli 5 66 E. G. RICHARDSON log W: log V on Fig. 3. The slope of these curves gives the appropriate value of n at each value of V. 3 4 5 Time (sees.) Fig. 2. Rate of fall of fishes Table I. Resistance measurements. Mackerel. Weight in air 1OC3 gm., in water 267 gm., volume 123 c.c. W gm. 267 40-5 480 650 Fcm./sec 6-65 n-o 125 13-5 Rough wooden model. Weight in air 151 gm., in water 267 gm., volume 130 c.c. W 267 41-5 48-2 65-0 V 83 100 i2-o 13-3 Wooden model smoothed and varnished. W 267 41 -5 45-0 V 8-3 12-0 12-5 Herring. Weight in air 864 gm., in water 13-8 gm., volume 72-6 c.c. W 13-8 230 31-2 V S'O 100 12-0 Rough wooden model. Weight in air 84-2 gm., in water 13-9 gm., volume 70-3 c.c. W 13-9 23-0 31-0 V 5-0 9-0 no Wooden model smoothed and varnished. W 13-9 188 23-0 31-3 V 5"25 8'0 IO-O I2'2 The general conclusion to be drawn from this table and the graphs is that the fish has a slightly less resistance than the rough wooden model, but that a carefully smoothed and polished wooden model can improve on this, particularly at the low speeds. The exponent n given by the slope of the curves of Fig. 3 varies from i-o to i-8 for the fishes used, just below the turbulence regions to which Newton's law applies. It is probable that the normal velocity range covered by a fish lies below the turbulent regime except when it is spurred to violent movement. The Physical Aspects of Fish Locomotion 67 The experiments with the smoothed model covered with a light oil previous to immersion to imitate the mucus on the body of the fish did not indicate any marked • fish o rough model X varnished model 1-0 1-2 1-0, 0-6 0-8 1-0 1-2 1-4 log terminal V Fig. 3. Resistance of fishes. +4 Paraffin +2 I Interface between / / / liquid -2 0 I 2 Velocity (cm./sec.) Fig. 4. Velocity gradients in two liquids in relative motion. improvement on the resistance of the model at speeds below the critical. Both theory and practice, however, concur in indicating that the presence of a viscous layer, i.e. more viscous than the main body of the fluid in which it is immersed, 5-2 68 E. G. RICHARDSON delays the onset of turbulence. It is in fact the shearing force in the "boundary layer " of fluid close to the solid surface of an immersed obstacle that gives rise to instability which in turn leads to turbulence in the wake.
Load more

Recommended publications
  • Fish Locomotion: Recent Advances and New Directions
    MA07CH22-Lauder ARI 6 November 2014 13:40 Fish Locomotion: Recent Advances and New Directions George V. Lauder Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138; email: [email protected] Annu. Rev. Mar. Sci. 2015. 7:521–45 Keywords First published online as a Review in Advance on swimming, kinematics, hydrodynamics, robotics September 19, 2014 The Annual Review of Marine Science is online at Abstract marine.annualreviews.org Access provided by Harvard University on 01/07/15. For personal use only. Research on fish locomotion has expanded greatly in recent years as new This article’s doi: approaches have been brought to bear on a classical field of study. Detailed Annu. Rev. Marine. Sci. 2015.7:521-545. Downloaded from www.annualreviews.org 10.1146/annurev-marine-010814-015614 analyses of patterns of body and fin motion and the effects of these move- Copyright c 2015 by Annual Reviews. ments on water flow patterns have helped scientists understand the causes All rights reserved and effects of hydrodynamic patterns produced by swimming fish. Recent developments include the study of the center-of-mass motion of swimming fish and the use of volumetric imaging systems that allow three-dimensional instantaneous snapshots of wake flow patterns. The large numbers of swim- ming fish in the oceans and the vorticity present in fin and body wakes sup- port the hypothesis that fish contribute significantly to the mixing of ocean waters. New developments in fish robotics have enhanced understanding of the physical principles underlying aquatic propulsion and allowed intriguing biological features, such as the structure of shark skin, to be studied in detail.
    [Show full text]
  • Copyrighted Material
    Index INDEX Note: page numbers in italics refer to fi gures, those in bold refer to tables and boxes. abducens nerve 55 activity cycles 499–522 inhibition 485 absorption effi ciency 72 annual patterns 515, 516, 517–22 interactions 485–6 abyssal zone 393 circadian rhythms 505 prey 445 Acanthaster planci (Crown-of-Thorns Starfi sh) diel patterns 499, 500, 501–2, 503–4, reduction 484 579 504–7 aggressive mimicry 428, 432–3 Acanthocybium (Wahoo) 15 light-induced 499, 500, 501–2, 503–4, aggressive resemblance 425–6 Acanthodii 178, 179 505 aglomerular 52 Acanthomorpha 284–8, 289 lunar patterns 507–9 agnathans Acanthopterygii 291–325 seasonal 509–15 gills 59, 60 Atherinomorpha 293–6 semilunar patterns 507–9 osmoregulation 101, 102 characteristics 291–2 supra-annual patterns 515, 516, 517–22 phylogeny 202 distribution 349, 350 tidal patterns 506–7 ventilation 59, 60 jaws 291 see also migration see also hagfi shes; lampreys Mugilomorpha 292–3, 294 adaptive response 106 agnathous fi shes see jawless fi shes pelagic 405 adaptive zones 534 agonistic interactions 83–4, 485–8 Percomorpha 296–325 adenohypophysis 91, 92 chemically mediated 484 pharyngeal jaws 291 adenosine triphosphate (ATP) 57 sound production 461–2 phylogeny 292, 293, 294 adipose fi n 35 visual 479 spines 449, 450 adrenocorticotropic hormone (ACTH) 92 agricultural chemicals 605 Acanthothoraciformes 177 adrianichthyids 295 air breathing 60, 61–2, 62–4 acanthurids 318–19 adult fi shes 153, 154, 155–7 ammonia production 64, 100–1 Acanthuroidei 12, 318–19 death 156–7 amphibious 60 Acanthurus bahianus
    [Show full text]
  • Three Gray Classics on the Biomechanics of Animal Movement
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Harvard University - DASH Three Gray Classics on the Biomechanics of Animal Movement The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Lauder, G. V., Eric Tytell. 2004. Three Gray Classics on the Biomechanics of Animal Movement. Journal of Experimental Biology 207, no. 10: 1597–1599. doi:10.1242/jeb.00921. Published Version doi:10.1242/jeb.00921 Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:30510313 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Other Posted Material, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#LAA JEB Classics 1597 THREE GRAY CLASSICS locomotor kinematics, muscle dynamics, JEB Classics is an occasional ON THE BIOMECHANICS and computational fluid dynamic column, featuring historic analyses of animals moving through publications from The Journal of OF ANIMAL MOVEMENT water. Virtually every recent textbook in Experimental Biology. These the field either reproduces one of Gray’s articles, written by modern experts figures directly or includes illustrations in the field, discuss each classic that derive their inspiration from his paper’s impact on the field of figures (e.g. Alexander, 2003; Biewener, biology and their own work. A 2003). PDF of the original paper accompanies each article, and can be found on the journal’s In his 1933a paper, Gray aimed to website as supplemental data.
    [Show full text]
  • Swimming Speed Performance in Coral Reef Fishes
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Springer - Publisher Connector Coral Reefs (2007) 26:217–228 DOI 10.1007/s00338-007-0195-0 REPORT Swimming speed performance in coral reef fishes: field validations reveal distinct functional groups C. J. Fulton Received: 11 October 2006 / Accepted: 6 January 2007 / Published online: 7 February 2007 Ó Springer-Verlag 2007 Abstract Central to our understanding of locomotion of efficiency, maneuverability and speed in one mode in fishes are the performance implications of using of propulsion, pectoral swimming appears to be a different modes of swimming. Employing a unique particularly versatile form of locomotion, well suited to combination of laboratory performance trials and field a demersal lifestyle on coral reefs. observations of swimming speed, this study investi- gated the comparative performance of pectoral and Keywords Gait Á Pectoral Á Body-caudal Á body-caudal fin swimming within an entire assemblage Habitat-use Á Energetic of coral reef fishes (117 species 10 families). Field observations of swimming behaviour identified three primary modes: labriform (pectoral 70 spp.), subca- Introduction rangiform (body-caudal 29 spp.) and chaetodontiform (augmented body-caudal 18 spp.). While representa- Swimming performance can be crucial for the survival tive taxa from all three modes were capable of speeds of fishes by affecting their ability to access habitats, exceeding 50 cm s–1 during laboratory trials, only avoid predators and acquire food. Such essential daily pectoral-swimmers maintained such high speeds under tasks often require precise movements, bursts of speed, field conditions. Direct comparisons revealed that or prolonged periods of swimming depending on the pectoral-swimming species maintained field speeds at a habitat or predator–prey system involved (Videler remarkable 70% of their maximum (lab-tested) re- 1993; Plaut 2001; Castro-Santos 2005).
    [Show full text]
  • LOCOMOTION ENERGETICS of LEEDSICHTHYS PROBLEMATICUS (ACTINOPTERYGII, PACHYCORMIFORMES) by HUMBERTO G
    [Palaeontology, Vol. 61, Part 5, 2018, pp. 775–783] ASSESSING METABOLIC CONSTRAINTS ON THE MAXIMUM BODY SIZE OF ACTINOPTERYGIANS: LOCOMOTION ENERGETICS OF LEEDSICHTHYS PROBLEMATICUS (ACTINOPTERYGII, PACHYCORMIFORMES) by HUMBERTO G. FERRON 1,* ,BORJAHOLGADO2,* , JEFFREY J. LISTON3,4,5,6,CARLOSMARTINEZ-PEREZ 1,6 and HECTOR BOTELLA1 1Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de Valencia, C/Catedratic Jose Beltran Martınez 2, 46980, Paterna, Valencia Spain; [email protected], [email protected], [email protected] 2Laboratory of Systematics & Taphonomy of Fossil Vertebrates, Departamento de Geologia e Paleontologia, Museu Nacional/Universidade Federal do Riode Janeiro (UFRJ), Quinta da Boa Vista, s/n, S~ao Cristov ~ao, 20940-040, Rio de Janeiro, RJ Brazil; [email protected] 3Bayerische Staatssammlung fur€ Pal€aontologie und Geologie, Richard-Wagner-Straße 10, 80333, Munchen,€ Germany; [email protected], [email protected] 4National Museums Scotland, Chambers Street, Edinburgh, EH1 1JF, UK; [email protected] 5Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK; [email protected] 6School of Earth Sciences, University of Bristol, Bristol, BS8 1TQ, UK; [email protected], [email protected] *Corresponding authors Typescript received 21 October 2017; accepted in revised form 5 April 2018 Abstract: Maximum sizes attained by living actinoptery- weighing up to 44.9 tonnes would have been energetically gians are much smaller than those reached by chon- viable and suggests that similar body sizes could also be possi- drichthyans. Several factors, including the high metabolic ble among living taxa, discarding metabolic factors as likely requirements of bony fishes, have been proposed as possible body size constraints in actinopterygians.
    [Show full text]
  • Energetics and Behavior of Coral Reef Fishes During Oscillatory Swimming in a Simulated Wave Surge Travis M
    © 2019. Published by The Company of Biologists Ltd | Journal of Experimental Biology (2019) 222, jeb191791. doi:10.1242/jeb.191791 RESEARCH ARTICLE Energetics and behavior of coral reef fishes during oscillatory swimming in a simulated wave surge Travis M. Marcoux and Keith E. Korsmeyer* ABSTRACT exposure has been identified as an important factor affecting reef Oxygen consumption rates were measured for coral reef fishes fish distributions, with correlations with fish morphology and during swimming in a bidirectional, oscillatory pattern to simulate swimming performance (Bellwood and Wainwright, 2001; Fulton, station-holding in wave-induced, shallow-water flows. For all species 2010; Webb et al., 2010; Fulton et al., 2017). examined, increases in wave intensity, as simulated by increases in Coral reef fishes display a great diversity of body and fin shapes, frequency and amplitude of oscillation, yielded increased metabolic and also swimming gaits, or patterns of fin use for swimming (Price rates and net costs of swimming (NCOS; swimming metabolic rate et al., 2011; Fulton et al., 2013b; Pink and Fulton, 2014). Swimming minus standard metabolic rate). Comparing species with different mode in fishes can be divided into two broad functional groups: – swimming modes, the caudal fin swimming Kuhlia spp. (Kuhliidae) body caudal fin (BCF) swimming, using lateral undulations of – and simultaneous pectoral–caudal fin swimming Amphiprion ocellaris the body and caudal fin, and median paired fin (MPF) swimming, (Pomacentridae) turned around to face the direction of swimming involving movements of one or more median (dorsal and anal) or most of the time, whereas the median–paired fin (MPF) swimmers, paired (pectoral) fins, while the body is held rigid (Webb, 1998).
    [Show full text]
  • Dispersal Patterns, Active Behaviour, and Flow Environment During Early Life History of Coastal Cold Water Fishes
    Dispersal Patterns, Active Behaviour, and Flow Environment during Early Life History of Coastal Cold Water Fishes Ryan Stanley1*, Paul V. R. Snelgrove1,2, Brad deYoung3, Robert S. Gregory4 1 Ocean Sciences Centre and Biology Department, Memorial University of Newfoundland, St. John’s, Newfoundland, Canada, 2 Canada Research Chair in Boreal and Cold Ocean Systems, Memorial University of Newfoundland, St. John’s, Newfoundland, Canada, 3 Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John’s, Newfoundland, Canada, 4 Ecological Sciences Section and Centre of Expertise for Aquatic Habitat Research, Fisheries and Oceans Canada, St. John’s, Newfoundland, Canada Abstract During the pelagic larval phase, fish dispersal may be influenced passively by surface currents or actively determined by swimming behaviour. In situ observations of larval swimming are few given the constraints of field sampling. Active behaviour is therefore often inferred from spatial patterns in the field, laboratory studies, or hydrodynamic theory, but rarely are these approaches considered in concert. Ichthyoplankton survey data collected during 2004 and 2006 from coastal Newfoundland show that changes in spatial heterogeneity for multiple species do not conform to predictions based on passive transport. We evaluated the interaction of individual larvae with their environment by calculating Reynolds number as a function of ontogeny. Typically, larvae hatch into a viscous environment in which swimming is inefficient, and later grow into more efficient intermediate and inertial swimming environments. Swimming is therefore closely related to length, not only because of swimming capacity but also in how larvae experience viscosity. Six of eight species sampled demonstrated consistent changes in spatial patchiness and concomitant increases in spatial heterogeneity as they transitioned into more favourable hydrodynamic swimming environments, suggesting an active behavioural element to dispersal.
    [Show full text]
  • Hydrodynamics of Balistiform Swimming in the Picasso
    HYDRODYNAMICS OF BALISTIFORM SWIMMING IN THE PICASSO TRIGGERFISH, RHINECANTHUS ACULEATUS by HALE LOOFBOURROW BSc. University of British Columbia, 2006 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES (Zoology) THE UNIVERSITY OF BRITISH COLUMBIA (VANCOUVER) January 2009 © Hale Loofbourrow, 2009 ii Abstract Aquatic propulsion by means of undulatory movements of the median (dorsal and anal) fins is the primary mode of transport for the Picasso triggerfish (Rhinecanthus aculeatus). Known as balistiform locomotion, this form of propulsion is an adaptation for highly efficient movement within complex environments such as coral reefs. A principle component of balistiform locomotion has been the development of momentum enhancement, a fin-force multiplier that increases swimming efficiency. This study examines the kinematics and energetics of balistiform locomotion employing theoretical models of thrust, power, and efficiency. Thrust and power were calculated and compared with theoretical values modeled by Lighthill and Blake (1990). This model has heretofore not been thoroughly vetted and was tested for accuracy and applicability. Thrust force was estimated from resistance (drag) using a vertical dead drop to determine terminal velocity; power was calculated from oxygen consumption measurements at different speeds. The Lighthill and Blake (1990) model requires median fin kinematics (frequency, wavelength, amplitude, wave angle), which were measured from high-speed videography and followed statistically predicted trends with frequency being the dominant variable, and the others changing little or not at all with speed. Momentum enhancement was found to be 3.6, close to Lighthill and Blake’s (1990) theoretically predicted value of 2.5.
    [Show full text]
  • Kinematics of Ribbonfin Locomotion in the Bowfin, Amia Calva
    RESEARCH ARTICLE Kinematics of Ribbon‐Fin Locomotion in the Bowfin, Amia calva 1,2 KEVIN JAGNANDAN * AND CHRISTOPHER P. SANFORD1 1Department of Biology, Hofstra University, Hempstead, New York 2Department of Evolution, Ecology and Organismal Biology, University of California, Riverside, California ABSTRACT An elongated dorsal and/or anal ribbon‐fin to produce forward and backward propulsion has independently evolved in several groups of fishes. In these fishes, fin ray movements along the fin generate a series of waves that drive propulsion. There are no published data on the use of the dorsal ribbon‐fin in the basal freshwater bowfin, Amia calva. In this study, frequency, amplitude, wavelength, and wave speed along the fin were measured in Amia swimming at different speeds (up to 1.0 body length/sec) to understand how the ribbon‐fin generates propulsion. These wave properties were analyzed to (1) determine whether regional specialization occurs along the ribbon‐ fin, and (2) to reveal how the undulatory waves are used to control swimming speed. Wave properties were also compared between swimming with sole use of the ribbon‐fin, and swimming with simultaneous use of the ribbon and pectoral fins. Statistical analysis of ribbon‐fin kinematics revealed no differences in kinematic patterns along the ribbon‐fin, and that forward propulsive speed in Amia is controlled by the frequency of the wave in the ribbon‐fin, irrespective of the contribution of the pectoral fin. This study is the first kinematic analysis of the ribbon‐fin in a basal fish and the model species for Amiiform locomotion, providing a basis for understanding ribbon‐fin locomotion among a broad range of teleosts.
    [Show full text]
  • Morphology and Experimental Hydrodynamics of Fish Fin Control Surfaces George V
    556 IEEE JOURNAL OF OCEANIC ENGINEERING, VOL. 29, NO. 3, JULY 2004 Morphology and Experimental Hydrodynamics of Fish Fin Control Surfaces George V. Lauder and Eliot G. Drucker Abstract—Over the past 520 million years, the process of evo- lution has produced a diversity of nearly 25 000 species of fish. This diversity includes thousands of different fin designs which are largely the product of natural selection for locomotor performance. Fish fins can be grouped into two major categories: median and paired fins. Fins are typically supported at their base by a series of segmentally arranged bony or cartilaginous elements, and fish have extensive muscular control over fin conformation. Recent experimental hydrodynamic investigation of fish fin func- tion in a diversity of freely swimming fish (including sharks, stur- geon, trout, sunfish, and surfperch) has demonstrated the role of fins in propulsion and maneuvering. Fish pectoral fins generate either separate or linked vortex rings during propulsion, and the lateral forces generated by pectoral fins are of similar magnitudes to thrust force during slow swimming. Yawing maneuvers involve differentiation of hydrodynamic function between left and right fins via vortex ring reorientation. Low-aspect ratio pectoral fins in Fig. 1. Photograph of bluegill sunfish (Lepomis macrochirus) showing the sharks function to alter body pitch and induce vertical maneuvers configuration of median and paired fins in a representative spiny-finned fish. through conformational changes of the fin trailing edge. The dorsal fin of fish displays a diversity of hydrodynamic function, from a discrete thrust-generating propulsor acting I. INTRODUCTION independently from the body, to a stabilizer generating only side forces.
    [Show full text]
  • The Effects of Viscosity on the Axial Motor Pattern and Kinematics of the African Lungfish (Protopterus Annectens) During Lateral Undulatory Swimming
    1612 The Journal of Experimental Biology 211, 1612-1622 Published by The Company of Biologists 2008 doi:10.1242/jeb.013029 The effects of viscosity on the axial motor pattern and kinematics of the African lungfish (Protopterus annectens) during lateral undulatory swimming Angela M. Horner* and Bruce C. Jayne Department of Biological Sciences, University of Cincinnati, PO Box 210006, Cincinnati, OH 45221-0006, USA *Author for correspondence at present address: Department of Biological Sciences, Ohio University, Irvine Hall, Athens, OH 45701, USA (e-mail: [email protected]) Accepted 7 March 2008 SUMMARY Separate studies of terrestrial and aquatic locomotion are abundant, but research addressing locomotion in transitional environments (e.g. mud) is scant. The African lungfish (Protopterus annectens) moves in a gradation of water to mud conditions during seasonal droughts, and breathes air. Thus, the lungfish was an ideal organism for our study to determine the effects of a wide range of viscosities on lateral undulatory swimming and to simulate some of the muddy conditions early tetrapods may have encountered. Regardless of viscosity, several aspects of lungfish swimming were similar to those of other swimming vertebrates including: posteriorly propagated muscle activity that was unilateral and alternated between the left and right sides at each longitudinal location, and posterior increases in the amount of bending, the amplitude of muscle activity and the timing differences between muscle activity and bending. With increased viscosity (1–1000·cSt), significant increases occurred in the amount of lateral bending of the vertebral column and the amplitude of muscle activity, particularly in the most anterior sites, but the distance the fish traveled per tail beat decreased.
    [Show full text]
  • Fish Locomotion: Biology and Robotics of Body and Fin-Based Movements
    Fish Locomotion: Biology and Robotics of Body and Fin-Based Movements George V. Lauder and James L. Tangorra Abstract The study of fish locomotion provides a rich source of inspiration for the design of robotic devices. Fish exhibit an array of complex locomotor designs that involve both diversity of structures used to generate locomotor forces, and versatile behaviors to engage with the aquatic environment. The functional design of fish includes both a flexible body exhibiting undulatory motion as well as numerous control surfaces that enable fish to vector forces and execute rapid maneuvers in roll, pitch, and yaw directions. Patterns of body undulation have often been misunderstood, and fish with propulsive mechanics as diverse as tuna and eels can display similar patterns of body bending during swimming. Many of the often-cited classical locomotor categories are based on a misunderstanding of body and fin kinematics. Fish fins can exhibit remarkably complex conformational changes during propulsion, and do not function as flat plates but have individual mobile fin rays actuated by muscles at the fin base. Fin motion and surface bending in most fish is actively controlled. Even during steady horizontal locomotion, median fins such as the dorsal and anal fins function to balance torques and can contribute to thrust. Locomotion using body undulation is not achieved independently from fin motion, and the vast majority of fish locomotor patterns utilize both the body and fins. Robotic systems derived from fish templates can range from simple flexible plastic panels to more complex models of whole body and fin design. Experimental test platforms that represent individual fins or specific components of fish locomotor design allow for detailed testing of hydrodynamic and mechanical function.
    [Show full text]